1. Field of the Invention
This invention relates to surgical instrumentation and processes for the anterolateral surgical correction of such conditions as scoliosis, which is also known as curvature of the spine.
2. Description of the Related Technology
Scoliosis in humans may occur as a result of many different causes, including infection by a disease such as polio, paralytic diseases of neuromuscular etiology, or injury to the spinal column. However, the most common cause of scoliosis in first world countries is a genetically determined growth abnormality of the spinal column which most often characteristically causes the curve to develop when the children are passing from late childhood through adolescence. This condition is known as idiopathic scoliosis.
While prevention and bracing can be effective for some children who develop scoliosis, surgical treatment is commonly when employed when the spinal curvature is too pronounced to respond to bracing or when established curves threaten a normal productive, pain free adult life. The standard surgical treatment for scoliosis since the mid-1950""s has been an xe2x80x9cinstrumented spinal fusion,xe2x80x9d which typically involves the implantation of metal articles such as hooks or screws to the spinal column at each end of the curve. Retaining rods are then attached to the hooks or screws at the ends of the curve. Surgical instruments are then mechanically used to straighten the spinal column (by twisting the spinal column or jacking it up) and the rods are then attached to the hooks or screws and fixed into place to maintain the position of the spinal column in the lengthened, straightened and corrected position. Surgery may be performed using the anterolateral approach, in which correction of the vertebrae is performed from the patient""s front or side or the posterior correction method in which correction of the vertebrae is performed from the rear.
To prevent subsequent loosening of the implants and loss of correction of the deformity, a spinal fusion of the instrumented section of the spinal column is virtually always performed at the same time as the instrumentation. This means that bone chips are placed along portions of the spinal column not covered by the implants. These bone chips or grafts induce the vertebrae which were part of the curvature to grow together (fuse) over a period of weeks to months to years. This fusion maintains the correction of the spinal deformity achieved by the application of the instruments (implants).
Current surgical approaches to spinal instrumentation tend to correct the curvature incompletely, and typically instrument and fuse long segments of the spinal column, most usually 7-14 segments. Such an extensive procedure is unavoidably traumatic to the patient and requires a great deal of recovery time, sometimes more than a year.
In addition, current approaches leave behind spinal implants which, because of their size and bulk, commonly cause problems after their implantation. The profile of these implants, which can be defined as their distance of extension beyond the normal vertebral structure of the patient""s spine, can interfere with the muscle in the lumbar spine such as the iliopsoas muscle, the nerves of the lumbar plexus and other critical anatomical structure such as ribs, blood vessels, lungs, the liver and the heart. One such approach is depicted in FIG. 1. This approach, which is described in great detail in U.S. Pat. No. 5,603,714, includes a system 10 for fusing a number of vertebral bodies 12 that utilizes a number of staple elements 14 that have tines for penetrating the vertebral body. As may be seen in FIG. 1, each staple element 14 is anchored to a respective vertebral body 12 by a pair of vertebral screws 16, which extend through apertures 18 defined in the staple elements 14 and each of which includes a threaded portion 20 for penetrating the vertebral body and a head portion 22. Each head portion 22 has a channel 24 defined therein for receiving a retaining rod 26. Each head portion 22 further includes a set screw 28 for finally securing the vertebral screw 16 to the retaining rod 26 at the conclusion of the surgical procedure. As may be seen in FIG. 1, the head portions 22 of the vertebral screws 16 extend significantly beyond the circumferential outer surfaces of the vertebral bodies 12. Accordingly, the system may be said to have a relatively high profile.
A need exists for an improved system and method for performing corrective surgery for spinal conditions such as scoliosis that is less traumatic to and facilitates a more rapid recovery for the patient, and that utilizes implants that present fewer postsurgical problems to the surrounding anatomy of the patient.
Accordingly, it is an object of the invention to provide an improved system and method for performing corrective surgery for spinal conditions such as scoliosis that is less traumatic to and facilitates a more rapid recovery for the patient, and that utilizes implants that present fewer postsurgical problems to the surrounding anatomy of the patient.
In order to achieve the above and other objects of the invention, a surgical implant spinal staple according to a first aspect of the invention includes a main body portion having an inner surface that is constructed and arranged to engage a vertebral body, an outer surface and means for receiving a fastener for the purpose of fastening the spinal staple to a vertebral body; a plurality of tine members extending from the inner surface, the tine members being constructed and arranged to penetrate the vertebral body in order to anchor the spinal staple to the vertebral body; and rod attachment structure for permitting a retaining rod to be attached to the main body portion, the rod attachment structure being integral with the main body portion.
According to a second aspect of the invention, a method of performing a surgical spinal fusion procedure to correct an abnormal spinal curvature includes steps of surgically approaching a patient""s spine; completely removing at least one intervertebral disc in an area of abnormal spinal curvature; realigning those vertebral bodies that were adjacent to at least one of the removed disks; compressing said vertebral bodies so as to achieve bone-to-bone apposition therebetween; and completing the spinal fusion procedure so as to secure the vertebral bodies in bone-to bone contact, thereby promoting relatively rapid healing of the fused area.
According to a third aspect of the invention, a method of performing a surgical spinal fusion procedure to correct an abnormal spinal curvature includes steps of surgically approaching a patient""s spine; aligning the spine to a desired, corrected position; sculpting at least one of the vertebral bodies so as to form a recessed area; attaching a spinal implant staple within the recessed area, whereby the spinal implant staple will have a lower profile than it would have the recessed area not been sculpted; and securing a retaining rod to the spinal implant staple.
These and various other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.